The rubbery and soft nature of a tennis ball makes for incredible slow motion videos.
As a tennis racket hits the optic yellow ball, it turns into a flattened sludge. Unbelievably, the slower the video runs, the more goo-like are the tennis balls.
At a point in the video, the tennis ball flattens itself so that it literally disappears inside the tennis racket. Watch the incredible slo-mo video below: